Beamforming is a spatial filtering technique that is used in a wide variety of fields and applications, such as wireless communication, ultrasound imaging and other medical imaging modalities, radar, sonar, radio-astronomy and seismology, among others. Beamforming techniques for ultrasound imaging are described, for example, by Steinberg, in “Digital Beamforming in Ultrasound,” IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, volume 39, number 6, 1992, pages 716-721, which is incorporated herein by reference.
Tur et al. describe efficient ultrasound signal sampling techniques, in “Innovation Rate Sampling of Pulse Streams with Application to Ultrasound Imaging,” IEEE Transactions on Signal Processing, volume 59, number 4, 2011, pages 1827-1842, which is incorporated herein by reference. Wagner et al. describe beamforming techniques applied to sub-Nyquist samples of received ultrasound signals, in “Compressed Beamforming in Ultrasound Imaging,” IEEE Transactions on Signal Processing, volume 60, number 9, September, 2012, pages 4643-4657, which is incorporated herein by reference.